Cardiac valve implantation is well known in the art. Less well addressed is how to detect possible leaks between the valve and surrounding blood vessel, how to seal such leaks, or how to design the valve such that it automatically seals the leaks.
Machiraju in U.S. Pat. No. 5,554,184, entitled “HEART VALVE”, describes a heart valve and a technique for effecting valve replacement or repair, which partially or completely replaces the mitral (or tricuspid) valve with an autologous graft from the pericardium, fascia lata or even the dura mater, or a bovine or porcine pericardial or other synthetic sheet material equivalent thereof, preferably in a configuration which substantially restores the original anatomy of the heart, including chordae tendineae attached to adjacent papillary muscles of the heart. Most preferably, a section of the patient's pericardium is cut to a shape including two leaflets, with each leaflet having a trabeculated tier of chordae tendineae terminating in a spear-shaped tab. The two leaflets are cut out as a single unit, and the two far ends are sutured together to yield a bileaflet valve having appended chordae and tabs.
Machiraju does not address leaks that can occur around the implanted valve.
Schreck in U.S. Pat. No. 6,454,799, entitled, “MINIMALLY-INVASIVE HEART VALVES AND METHODS OF USE”, describes expandable heart valves for minimally invasive valve replacement surgeries. In a first embodiment, an expandable pre-assembled heart valve includes a plastically-expandable annular base having a plurality of upstanding commissure posts. A tubular flexible member including a prosthetic section and a fabric section is provided, with the prosthetic section being connected to the commissure posts and defining leaflets therebetween, and the fabric section being attached to the annular base. In a second embodiment, an expandable heart valve includes an annular tissue-engaging base and a subassembly having an elastic wireform and a plurality of leaflets connected thereto. The annular base and subassembly are separately stored and connected just prior to delivery to the host annulus. Preferably the leaflet subassembly is stored in its relaxed configuration to avoid deformation of the leaflets. The expandable heart valves may be implanted using a balloon catheter. Preferably the leaflets of the heart valves are secured to the commissure regions of the expandable stents using a clamping arrangement to reduce stress.
Schreck also does not address leaks that can occur around the implanted valve.
Amplatz in U.S. Pat. No. 6,638,257, entitled, “INTRAVASCULAR FLOW RESTRICTOR,” describes an intravascular flow restrictor that comprises a braided tubular structure designed to be placed in the main pulmonary artery for limiting blood pressure in the lungs. The braided structure is designed to be collapsed for placement in a delivery catheter, but when it is ejected from the delivery catheter, it assumes a substantially larger diameter disk shaped device having one or more longitudinal channels or passways therethrough.
Amplatz also does not address leaks that can occur around the implanted valve. In addition, Amplatz's braided structures are of a shape and size not appropriate for paravalvular leak detection and sealing. Their geometry is designed for the conditions of the transceptal hole and not appropriate for valve leakage.
Spenser et al. in U.S. Patent Application No. 20030153974, entitled “IMPLANTABLE PROSTHETIC VALVE”, describe a prosthesis device suitable for implantation in body ducts. The device comprises a support stent bring comprised of a deployable construction adapted to be initially crimped in a narrow configuration suitable for catheterization through a body duct to a target location and adapted to be deployed by exerting substantially radial forces from within by means of a deployment device to a deployed state in the target location, the support stent bring provided with a plurality of longitudinally rigid support beams of fixed length, and (2) a valve assembly comprising a flexible conduit having an inlet end and an outlet, made of pliant material attached to the support beams providing collapsible slack portions of the conduit at the outlet. When flow is allowed to pass through the valve prosthesis device from the inlet to the outlet, the valve assembly is kept in an open position, whereas a reverse flow is prevented as the collapsible slack portions of the valve assembly collapse inwardly to provide blockage to the reverse flow.
Spenser et al. also do not address leaks that can occur around the implanted valve.
With regard to the general topic of prosthetic valves, implantation is currently done either through open heart surgery or by use of newer percutaneous methods, some of which are described in the patents mentioned above. With both methods paravalvular leaks are a known side effect. One way to approach the leak problem is to identify the leak location and repair it. Another approach is to equip the prosthesis with means to prevent the leak (“self-sealing” prosthesis). Both these approaches are encompassed by the present invention.
Percutaneous introduction of medical devices is a preferred surgical procedure for it involves making only a very small perforation in the patient's skin (usually in the groin or armpit area) under local anesthetic sedation. In contrast, surgical placement involves a large chest, surgical incision and requires general anesthesia, to expose a large portion of a patient's thoracic region. Percutaneous introduction is therefore considered safer and less invasive.
Percutaneous introduction of a leak detection and repair device or of a self-sealing valve resembles other known interventional cardiologic procedures. The percutaneous deployment procedure and device has an impact on several parameters of the product design, some of which are explained hereinafter.
In summary, the present invention provides new concepts of percutaneous paravalvular repair, including means for identifying the leak location, repair techniques, and means for leak prevention that can be engineered into the prosthesis valve itself.